Electron tube



vPatented Oct. .27, 1925.l

jVUNiTE-D' STATES.

PATENT oFFlcE.

SAMUEL RUBEN, 0F NEW YORK, N. Y.l

Applica-tion led June 30, 1920. Serial No. 898,'140.

' To all whom; 'it kmay concern:

Be it known that I, SAMUEL RUBEN, a citizen of the lUnited States,residing atNew York, in the county of New York and State '-o'f New York,have invented certain new fied current to fluctuate in accordance withthefluctuations in a variable current circuit such, for instance, as thecircuit of a line or radio telephone transmitter or a telegraph circuit.vIn carrying out the invention, I

provide an exhausted tube or casing, Within which is arranged anelectron emission element, such as a filament, and a primary anode,opposed to the `filament, and these are connected so that the electrons`emitted from the filament will flow to said anode.l Between thefilament and said anode, I arrange a secondary anode in a circuit whichvin- :ludes the primary anode, and this secondary anode vforms a screenbetween the filament and the primary anode, for cutting off the electronflow between the filament and primary anode, except such electrons asare directed through an opening formed in the secondary anode. Adjacentthe filament, I provide a concentrating element for causing theelzctrons emitted from the filament to converge vor focus at the openingin the secondary anode and pass through said opening to the primaryanode. This concen- .rating element, when connected in a variablecurrent circuit, such as the circuit of a telephone transmitter, causesvariations in the focusing point of the electron stream, so`

that more or less of the electrons pass through the opening to theprimary anode, in accordance with the fluctuations in said variable'current circuit. The primary anode forms a secondary source of electronemissions, and electrons emitted from the filament and striking saidprimary anode cause a much greater number of electrons. to be emittedfrom said anode than are emitted from the filament. These secondaryemissionsflow to the secondary anode, which is included in circuit withthe primary anode and with a suitable battery or generator, and anamplified current flows in this latter circuit and varies in accordancewith the fluctuations -in the telephone or signaling circuit.

In the accompanying drawing, the elec-l' ,tron tube isjshown inlongitudinal central sectlon and a simple'arrangement of circuits isshown in connection with the tube, for the purpose of illustration.

Referring to the drawing, T indicates the casing or tube proper,'preferably made 0f pyrex, 1n orderl to withstand a considerable vdergree of heat without breakage; The tube is formed with an enlargedcentral portion t, which affords a large heat radiating sur' face, andwhen the tube is arranged vertically, as shown in the drawing, the airliowmg upwardly around the bulbous portion a carries ofl` the heat. Inthe upper half of the tube is arranged a Ametal stem 1,y

which projects downwardly toward the bulbous portion of the tube, andupon the lower end of this stem is secured a cup of insulating material2, preferably of lava, within which is arranged a spiral filament 3.This lament has one end connected to the rod 1, and its other endconnected toa conductor 4 which yleads .out through the upper end of thetube. Another conductor 5 extends through the upper end of the tube andis connected to the'rod 1. When current is applied to the conductors'4and 5 from a suitable current source, the filamentl will be heatedthereby. A rod 6, fused intor the lower part of the tube, projects up.-wardly into the bulbous portion and carries a metal plate 7, which plateis preferably in the form of a disk and has a .convex surface opposed tothe filament 3. For convenience, the plate 7 will be referred to as theprimary anode.

A rod 8, fused into a branch 9 of the tube, carries a secondary anode10, consisting of a concavo-convex metal body having its concave faceopposed to the convex face of the primary anode 7 and substantiallyconcenis substantially concentric with a line passing from the center ofthe filament through the center of the opening 10a to the primary anode.The ring 11 is also adjustable longitudinally upon the cylindrical partof the lube. This ring, as hereinafter explanned, serves as a dcflecloror concentrator, l'or deflecting the electron sti-cani emitted from thefilament and causing it to concintrate in the opening 1U, from whence itfiows through to the primary anode 7, as indicated by the dotted linese. By varying the position of the ring the concentration of the electronstream may be varied, as will be explained.

In the diagrammatic arrangement of circuits shown in the drawing, thefilament conductors 4 and 5 are connected to a battery A by conductors 4and 5, respectively, this battery furnishingr current to heat thefilament so that the latter will emit electrons. The concentrator 11 isconnected to one terminal of a variable current source, the otherterminal of said source being connected to the filament. This variablecurrent source may be a telegraph or a telephone transmitter circuit andin the drawing a telephone transmitter circuit is shown. The primary ofthe telephone transmitter circuit is indicated at 12, and the oppositesides of the secondary circuit, 13 and 14;, are shown connected to thefilament and concentrator, respectively. The wire 5a, Which is connectedto one terminal of the filament and also to the concentrator, extends toone terminal of a battery B, and the other terminal of this battery isconnected by conductors 15 and 8 to the secondary anode 10 of the tube.Another conductor 16 leads from an intermediate portion of the batteryB, through the primary 17 of an induction coil w, to the rod 6, Which isconnected to the primary anode 7.

The arrangement of circuits shown provides a heating circuit Whichincludes the filament and the battery A; a charging circuit whichextends from one terminal of the battery B through conductors 5a and 5to the filament and from an intermediate portion of battery B, throughconductor 16, coil 17 and rod 6 to the primary anode 7; a dischargingcircuit Which includes a portion of battery B and extends' from oneterminal of said battery, through conductors 15 and 8 to the ,secondaryanode 10, and from an intermediate portion of the battery throughconductor 1:6, coil 17 and rod 6 to the primary a-node 7; and a circuitleading from a source of variable currents and connecting theconcentrator to one terminal of the filament and one terminal of thebattery B.

In operation, with the arrangement of circuits shown, the filament isheated by current from the battery A and electrons are given ofi" whichwould flow in parallel lines to the primary anode 7 but for theinterposition of the secondary anode 10 and the proximity of theconcentrator ring. With the concentrator ring and the secondary anodepresent, as shown in the drawing, the electron stream indicated at cwill be deflccted, and by proper adjustment of the concentrator ring thestream will be focused in the' opening 10 and will thence diverge andthe electrons will strike against the primary anode 7, this anode beingone terminal of the charging .circuit which, as above explained,includes a portion of the battery B. the filament being the otherterminal of said circuit. The plate 7 is, however, one terminal ofanothery circuit, which includes the secondary anode 10 and has beendescribed as the discharging circuit, including, as it docs, a portionof the battery B and the primary of the induction coil 17. lVhen theelectrons emanating from the filament strike the primary anode 7, a muchgreater number of electrons are emitted from this primary anode andthese will flow in a diverging stream, as indicated by the dotted linesf, from the primary to the secondary anode and through the dischargingcircuit of which these anodes are the terminals. As the electrons takethe shortest course between the opposing surfaces, and as these surfacesare concentric, it will be evident that the electron stream will bedivergent and that very few of the electrons will fiow from the primaryanode toward the point of concentration of the electrons iowing from thefilament, at the opening 10a.

If, now, the concentrator ring or band is affected by a Variablepotential in the telephone or signaling circuit, its repellant actionupon the electrons Will vary accordingly and cause like variation in thefocusing point of the electron stream. As the 'focusing point varies sowill the number of electrons passing through the opening in thesecondary anode to the primary anode vary.

This will cause variations in the number of 1 electrons emitted from theprimary anode and flowing to the secondary anode. Hence, the current inthe charging and discharging circuits will Vary according to thefluctuations in the signaling circuit. As the number of electronsemitted in the discharging circuit is much greater than in the chargingcircuit, an amplified current will flow in the discharging circuit Whichincludes the primary winding 17, and high tension impulses at properfrequency will be generated in the secondary Winding 17a of thetransformer w, which is connected to the aerial g.

It will be understood ythat the arrangement of circuits shown is merelyfor purpose of illustration and that the tube may be connected up invarious arrangements of circuits and for various purposes.

I have found it to be of great advantage to calorize all of theconducting parts Within the tube except the filament and the primaryanode, as calorization decreases the amount of occluded gas in the metaland decreases the electron emission fromv the calorized parts; also, byreason of the reduction in the occluded gases in the metal thevacuum inthe tube is better preserved, and the calorized parts are capable ofwithstanding greater heat.

What I claim is: l. An electron tube comprising a thermionic emissionelement, a primary anode, a. secondary anode interposed between said felement and primary anode, said secondary anode having an openingtherethrough, and means adapted to be connected to a variable currentsource for focusin the electron stream passing between sai element andprimary anode in said opening.

2. An electron tube comprising a thermionic emission element, a primaryanode,

a lsecondaryanode interposed between said element and primary anode,said secondary anode having an opening th^rethrough, and adjustablemeans adapted to be connected to a variable current source for focusingthe electron stream passi-ng between said element and rimary anode insaid opening.

l3. An e ectron tube comprising a thermionic'emission element, a primaryanode, aY

secondary anode interposed between said element and vprimary anode, saidsecondary anode having an opening therethrough, and an annularconducting element concentric with the vaxis of the electron streampassing between said emission element and primary anode and adapted tobe connected to a parallel withthe axis of said ,streamv and adapted tobe connected to aVv variable current source. f

5. An 'electron tube comprising' a thermionic emission element,a primaryanode,

a secondary anode interposed between said element and primary anode,saidsecondary anode having an opening therethrough, a

concentrating element for focusing the electron stream in said opening,and a vvariable current source connected to said concentrat. ingelement.'

6. In an electron tube, a lthermionic emis' sion element, a primaryanode, a secondary anode between sald element and primary anode, saidanodes .having parallel opposed faces. and said secondary anode havingan openlngtherethrough, and means adapted to be connected to a variablecurrent source for focusing Athe electron stream emitted from saidelement in said o enin'g.

7. In an electron tube, a t ermiomc emission element, a primary anodehaving' a convex surface, a seconda-ry anode interposed between saidelement and primary' anode and having a concave surface opposed to theconvex surface of the primary anode,v

said secondary anode having an opening in line with sai element andprimary anode, and means for focusing the electron stream emitted fromsaid element .in said opening.

8. An electron tube comprising a thermionic emission element, a primaryanode, a secondary .anode interposed between said element and said'primary anode, said secondary anode having a focusing orificetherethrough, means for focusing the elec- L tron stream in saidopening, including a source of varlable currents, a charging-circuitincluding said elements and said rimary anode, and a discharging circuitj including said vprimary and secondary anodes.

In testimony whereof'I affix my signature.` gli SAMUEL RUBEN.

